Hiding vertices from Automatic Weights process?
UPDATE: I have found a workaround that seems to solve the problem. I don't know if there is a smarter way, but I'll post it for anyone else with a similar issue.


I selected all the vertices that made up the problematic area, pressed P and separated by "Selection".
I then select my mesh (which is now separated from the problematic vertices), go to Weight Paint mode and then do Automatic Weights binding.
After weighting process is complete, I select the seperated mesh, then shift-select my main mesh and do Ctrl+J to join them again.
Then I go back to weight paint mode and click the bone nearest to this area and manually paint it so it follows the rig.
Finally, I manually merge (Alt+M) EACH INDIVIDUAL vertex at the points where they were cut/separated.


This solved the problem, and it even kept the shape keys I had in that area from being destroyed, since no vertices was added or removed by doing this. If anyone have a smarter method, I would still love to hear it!